Smart fixes for damaged balcony slabs

A technical article on structural assessment and modernization options

When renovating existing balconies, many developers, architects, and construction companies regularly encounter a recurring problem: damaged concrete slabs. This construction method was standard practice for decades – but today, its renovation is often complex, costly, and associated with uncertainties regarding long-term performance.

Conventional balcony renovation in existing buildings – process and challenges

The refurbishment of old reinforced concrete balconies follows established technical standards but involves considerable structural and financial effort.

1. Damage analysis
First, the condition of the balcony slab is assessed. Typical types of damage include:

• Cracks and spalling caused by carbonated concrete
• Reinforcement corrosion due to chloride penetration
• Insufficient concrete cover and reduced load-bearing capacity

In addition, tests such as chloride content analysis, measurement of carbonation depth, and, where necessary, ultrasonic or radar investigations are required.

2. Demolition and exposure
Defective concrete areas are completely removed, and the reinforcement is exposed and cleaned.

3. Corrosion protection
The exposed reinforcement is treated with a suitable corrosion protection system in accordance with applicable standards.

4. Reprofiling
Damaged areas are rebuilt using special repair mortars as specified by local regulations, restoring the concrete cover.

5. Waterproofing and surface protection
A standard-compliant waterproofing system with functional drainage, proper slope, and protective surface coatings is applied to prevent future damage.

6. Finishing works
Finally, a new surface layer or balcony flooring is installed to complete the renovation.